Re: TChain

Rene Brun (Rene.Brun@cern.ch)
Thu, 05 Mar 1998 15:27:59 +0100


Laurent,
In your example below, simply change the statement:
nt->Draw("Krun");
to
ch->Draw("Krun")
and your program will work correctly.

Rene Brun

Laurent Mirabito wrote:
>
> Hello,
>
> I have the following problem using TChain
> I created one TTree per run and I tried to Draw variable using TChain:
>
> root [4] TChain ch("nt")
> root [5] ch.Add("Cluster20638.root")
> root [6] ch.Add("Cluster20637.root")
> root [7] ch.ls()
> OBJ: TChainElement nt Cluster20638.root : 0
> OBJ: TChainElement nt Cluster20637.root : 0
> root [8] nt->Print()
> Error: No symbol nt->Print() in current scope FILE:/tmp/17867haa LINE:1
> root [9] nt->Draw("Krun")
> Error: No symbol nt->Draw("Krun") in current scope FILE:/tmp/17867iaa
> LINE:1
> But when I open file by file it works
> root [0] TFile f("Cluster20638.root")
> root [1] f.ls()
> TFile** Cluster20638.root
> TFile* Cluster20638.root
> KEY: TTree nt;1 An example of a ROOT tree
> root [2] nt->Print()
> ************************************************************************************
> *Tree :nt : An example of a ROOT
> tree *
> *Entries : 17430 : Total Size = 662542 bytes File Size =
> 208130 bytes *
> * : : Tree compression factor =
> 4.12 *
> ************************************************************************************
> *Branch :Krun :
> Krun/I *
> *Entries : 17430 : Total Size = 49994 bytes File Size =
> 230 bytes *
> *Baskets : 2 : Basket Size = 25000 bytes Compression=
> 217.37 *
> *..................................................................................*
> *Branch :Kevt :
> Kevt/I *
> *Entries : 17430 : Total Size = 49994 bytes File Size =
> 17564 bytes *
> *Baskets : 2 : Basket Size = 25000 bytes Compression=
> 2.85 *
> *..................................................................................*
> *Branch :Nclus :
> Nclus/i *
> *Entries : 17430 : Total Size = 49996 bytes File Size =
> 6198 bytes *
> *Baskets : 2 : Basket Size = 25000 bytes Compression=
> 8.07 *
> *..................................................................................*
> *Branch :Idet :
> Idet/i *
> *Entries : 17430 : Total Size = 49994 bytes File Size =
> 3309 bytes *
> *Baskets : 2 : Basket Size = 25000 bytes Compression=
> 15.11 *
> *..................................................................................*
> *Branch :Vclu :
> Vclu/F *
> *Entries : 17430 : Total Size = 49994 bytes File Size =
> 22553 bytes *
> *Baskets : 2 : Basket Size = 25000 bytes Compression=
> 2.22 *
> *..................................................................................*
> *Branch :Noiclu :
> Noiclu/F *
> *Entries : 17430 : Total Size = 49998 bytes File Size =
> 18954 bytes *
> *Baskets : 2 : Basket Size = 25000 bytes Compression=
> 2.64 *
> *..................................................................................*
> *Branch :Xclu :
> Xclu/F *
> *Entries : 17430 : Total Size = 49994 bytes File Size =
> 22081 bytes *
> *Baskets : 2 : Basket Size = 25000 bytes Compression=
> 2.26
>
> ...
>
> Any Ideas ?
> Best regards
> Laurent
> --
> Laurent Mirabito
> IPN Lyon